The Truth About Muscle Loss When Dieting

August 31, 2018 | 103 Comments

muscle loss
Muscles are like lizard tails – they can come back if you lose them.

People worry about the weirdest and most irrelevant things when dieting. When you’re dieting, your #1 goal is to lose weight (fat specifically), nothing more, nothing less. You should only be worried about how you’re going to create a calorie deficit for the day.

However minds begin to wonder, goals get distorted, and people begin coming up with these crazy “what if” scenarios.

“What if I eat less and my metabolism slows down?” – Nothing to worry about, covered that here.

“What if I lose weight but regain it all back?” – Then you’re not a very long-term minded person, are you?

“What if I go on a diet, become insanely sexy, and end up causing head-turning car collisions which in turn gets me arrested because of said sexiness and I get a life sentence in a maximum security prison?” – Completely legitimate concern, but that’s just a risk you have to be willing to take.

“What if I lose all my hard-earned muscle while dieting?” – Read the rest of the article.

Muscle loss while dieting is nothing to worry about

I completely understand people’s fear of losing muscle while dieting but the truth is that it’s nothing to worry about.

You see, muscle loss is transient. It’s not permanent. 

So even if you do somehow manage to lose 5 pounds of muscle while dieting, whether it’s due to an illness, extremely low protein intake or lack of resistance training…you’re guaranteed regain that loss once you begin eating normal and resume resistance training.

This is all thanks to muscle memory, which unlike muscle confusion, is a real thing.

Why the hell are you worried about muscle loss?

As long as you’re getting an adequate amount of protein…

As long as you’re consistently weight training while on your diet…

As long as you don’t go on any crazy crash sub 1000 calorie diets….

You’re probably not going to lose any muscle mass. And even if you do manage to lose some… the amount will be minuscule.

Focus on losing body fat, because that’s the hard part. Worrying about muscle loss is just counter-productive.

Once you’re at your desired level of leanness, gaining back any lost muscle will be a relatively easy thing to do.

It’s the mindset of “Oh I should eat more food because I’ll lose muscle” that’s hurting your progress. The only thing eating more food will do is make you fat.

Saying that you should eat more while dieting is just a lame cop out for those who don’t have the discipline of consistently eating less.

Photo Credit – Nuno R.

103 Comments - Leave Your Thoughts

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  1. Dear Keith,

    i am now 27 y.o, had been doing weight trainings quite frequently for the passed 2 years and started to train consistently 4 days + 2-3 cardio sessions/week since August; but i did went for travelling for 2 weeks twice during the period;

    my daily protein intake is around 1.2-1.5g/lbs and carbs around 100-120g daily, fat would be less than 50/day.

    but it seems to me that my progress is quite slow?
    i started with (August) 77.8kg, 22.7% body fat, 57kg muscle mass -> 80.9kg, 23.2% bf, 58.9kg muscle mass (December) and now i am at 79.3kg, 21.5% bf, 59kg muscle mass(march)

    had been in calorie deficit for the passed 2 months already but the progress seems slow to me.

    Do you think i should proceed with more cardio and lessen my protein intake to get myself down to around 15% body fat?

    Thank you.

    1. 1.2-1.5g for protein is unnecessary. 1g max is what i recommend. Even 0.8 is fine.

      Are you sure you’re in a deficit? A lot of time people are simply not tracking accurately.

  2. I just did 90 days of the strict keto diet with only a 6 hour eating window each day, fasting during all other hours. The only exercise I was doing was walking 5 to 7 miles per day. I lost a total of 48lbs, but over 20 of that was lean muscle mass. (Dexa body scan before and after diet) I did 200 grams of protein a day, mostly whey protein powder, eggs, sardines, whole chicken and steak. I lost 28 lbs of fat, but am shocked at the amount of lean muscle mass also lost. Total calorie intake was about 1800 – 2000 per day, but I felt amazing. Brain fog was gone and I went down 2 pant sizes. I never felt like I was starving myself and felt like I could keep going with this keto lifestyle. I had plenty of energy and slept better than ever.

    Yesterday, after reviewing my scan results, my doctor told me to go off Keto and resume a normal diet due to concerns about the lean muscle loss. I ate one bowl of milk and Life cereal and a small slice of cheese pizza for dinner and hours later thought I was going to die. It was a long, miserable night. I bloated up like a cow eating too much raw alfalfa. Prior to keto, Life cereal and pizza were several times a week staples. What is up with this? Is 20 lbs of muscle loss really that big of a deal? My doctor is worried I did metabolic damage.

      1. But 20 lbs in 90 days? A little bit would not have surprised me. But consuming 200+ grams of protein a day was supposed to be a protection from massive lean muscle loss, right? Or is resistance training absolutely necessary?

        1. Dexa shows water and glycogen inside the muscle as muscle too.
          In Keto your glycogen and water in the muscles reduce significantly and so 20lbs is not loss of muscle fibre.

          you can also check youtube for videos,If you are on Keto ,break it do bodybuilding style carb loading and then do the scan to get a better idea of actual muscle lost.

  3. Hey Keith,
    I did a crash dieting and lost a lot of weight mostly fat and I did only cardio and no resistance training,
    Right now my body is too loose ,is it possible to fix it if I loose fat correctly this time?

  4. I have lost a total of 123 lbs with about 80 more to go (I’m playing it by ear) following a paleo/keto diet. Over the last 3.5 months I lost 6% body fat and was thrilled until I calculated and discovered I had actually lost 3 lbs of lean mass. Is this something to be worried about? I could not work out two of those months because of an injury.

  5. Finally someone said it! Very refreshing. Stick with weight loss goal, do as much exercise as you can and/or want to and don’t detour. Worry about ‘muscle sculpting’ or whatever later. Just remain focused on initial goal. This type of thinking could be applied into several aspects of life too. Great article, thanks 😉

    1. well i never said don’t worry about muscle loss. I just said if you want to prevent most of it, then make sure you’re lifting weights.

      1. “Focus on losing body fat, because that’s the hard part. Worrying about muscle loss is just counter-productive.”

        That’s you, basically saying don’t worry about muscle loss…

        Make up your damn mind dude

  6. Cutting calories to lose weight WILL cause your resting metabolic rate to slow down, permanently. To say or think otherwise is merely an ill informed opinion, and completely ignores ALL the latest research on weight loss. Look this up people. Read the medical journals. The info is out there. Please do not rely on some guys blog.

  7. I agree losing a little is not the be all and end all but I think an increased focus on muscle retention in the dieting population is a good one. Most people who “diet” don’t turn around at the end and decide they are going to add muscle to their frame. They hit a number and are “done” now with a smaller BMR and a lower total energy expenditure because they aren’t carting a 20kg weight vest around. Neural strength aside, if you have lost 10kg of muscle as someone above mentioned what impact does this have on force output. Does it require Kore energy every future workout to shift a 50kg bar or an 80kg, a 12kg kettle or a 14 500 times? Not saying you can’t lose any but the mindset of retention is an important one too.

  8. I know this post is a few years old, but I came across it at the perfect time. I have lupus, and it has really messed up my shoulder. But I want to lose at least 20 lbs of fat. I was so worried that I’d lose the little muscle I had, that I would lift despite the shoulder pain. That’s the thing this muscle loss fear does to people. Plus, in trying to get the amount of protein I supposedly need, I was eating way too much (and making myself and family miserable). I want to be fit and lean … not a competitive bodybuilder. So, should I just focus on losing the fat and once the shoulder heals go back to lifting? It’s so easy just to give up, but I don’t want to do that. Thanks.

    1. depends how much fat you have to lose, but you should always be lifting (safely, of course) whether you’re trying to lose fat or not.

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